reflex0

If you can use pinch collar legally in your state, then there is no more problem for you.

http://www.youtube.com/watch?v=aWl1kQ18Zgg&feature=youtube_gdata_player

Good working dog always pick up something from ground. If you really want to train food refusal, you also need to think about what is the negative side of this training. I asked the same question to my trainer, what he said that is very very difficult and dog may have develop other negative effect. You may feed dog only away from the fence and install E fence to keep dog away from the fence.

I would use positive reinforcement for this type of behavior. Set up a 7 days program for the good behavior that you want by marker training. Day one: Use a clicker or voice to get your dog to associate with marker training. Do this before your dog eating. Click or say "Yes" Or "Good" then give treat (small treat) for 5 mins. then say "relax" to finished training. Do it 2-3 time for first day. Day 2: every time your dog watch you then mark it then reward for 5 mins. (even small turn his head toward you) 2-3 times for day2. Day 3: parked your car around your house, ask a helper who dog does know him or her to walk around the car. Start from far away as long as your dog does not show fear. then do the watch me training and ask helper to walk around the car until your dog starts show reaction then ask helper to walk back a bit until the dog focus on you again. (5 mins) If possible 2-3 time per day. Day 4: do the same as day 3, but getting closer. Day 5: change location such as local parking area, then do the focus training like day 3. start from far away as well. Day 6: do the same as day 4. Day 7: change location, helper and getting closer. All training before eating. if dog is not interested in food then do not feed dog for one day. This is slow training, please do not push too fast. If your dog doing really well during the training, then give the dog a jackpot which is a good amount of handful treat at one time and a lots of vocal reward. hope this training will make your dog reduce fear and focus on you.

Yes, those behaviors are normal for dog to dog play. Is this the first time you are having two dogs in your household? Do you know how to apply leadership amount two dogs? If I were you; I would not let two dogs play freely, because the adult dog will take over the leadership from you when he play with puppy. You should google it for more information in regarding how to manage multi-dogs household.